Yes, I cant think of a logical conclusion apart from an isolated and acutely short lasting mental health issue. and i don't believe in ghosts. Never seen one before or since.
I worked nights at a recycling plant, the landlady of the pub across the road was my supervisors Mr's and would open up for "Dinner" around 1 am we would go and have a pie and a pint and go back to work 2:30am. This night i knocked on the door to be let in (bolted door) i went in ordered a pint and went for a piss whilst she pulled it.
Whilst at the stone the regular creak of the auto shut bar went off door opened and an old bloke dressed in a shabby suit walked in. (I assumed it was the landlady's dad) The bloke just stood behind me at the piss stone and said nothing even after I asked if he was "alright mate" He stood there confused look on his face. (What i noticed was this large knot in his neck tie, it was probably about 2 inches wide) I thought poor bloke must have dementia or something so i finished my visit and went to pick up my pint. Not wanting to appear unkind I asked the landlady if the bloke in the toilet was ok? to which she replied, doors bolted Sprout, Faz(her fella) phoned and told me to tell you to get the beers in he will be 20 mins. I explained what happened and she said "oh that will be Albert, i've never seen him but he's goosed me a few times in the cellar".
Nobody left those toilets after me the bar was next to the door and it was one way in 1 way out and he wasn't there when i tried to show her that there was a punter in her bogs. My gaffer thought i had been on the piss before coming to work but i assure you, the first beer i had that day was the pint i ordered before have a slash. So a isolated psychotic episode, a piss take via a brilliant magic trick or an unexplainable phenomena ?